There has been a growing public health concern globally regarding the adverse health effects caused by the inhalation of fine and ultra-fine (submicroscopic/microscopic) particles. From the phenomenon of yellow dust dating back to ancient times to the Great Smog of London in 1952, ambient air contamination is ubiquitous and affects the world's population.
Atmospheric particulate matter or PM, is a mixture of solids and liquid droplets floating in the air. Some particles are released directly from a specific source, while others form in complicated chemical reactions in the atmosphere. PM2.5 is particulate matter of 2.5 μm or less in diameter. PM2.5 is generally described as fine particles. Ultra-fine particles are those with a diameter less than 0.1 μm or PM0.1.
It is generally recognized and well documented that smaller particles have been found to be more harmful long-term to human health. A study by the Bay Area Air Quality Management District entitled “Ultra-fine Particulate Matter Study in the San Francisco Bay Area” (release date 23 Aug. 2010) finds that PM0.1 can penetrate pulmonary tissue, enter the bloodstream, and circulate throughout the body, unlike larger particulates. Therefore, PM0.1 can damage a number of internal systems that are inaccessible to larger particles. Furthermore, according to the World Health Organization “Health Effects of Particulate Matter”, the health effects of inhalable PM are due to exposure over both the short term (hours, days) and long term (months, years) and include respiratory and cardiovascular morbidity, such as aggravation of asthma, respiratory symptoms and an increase in hospital admissions mortality from cardiovascular and respiratory diseases and from lung cancer.
People suffering from asthma and from cardiovascular diseases have been identified to be especially sensitive to air pollution (Palmgren et al., 2003). In epidemiological studies conducted over the past ten years, a very consistent quantitative picture has emerged between the levels of air pollution (especially fine fraction particles) and increases in morbidity and mortality (Palmgren et al., 2003). Furthermore, there is no evidence of a safe level of exposure or a threshold below which no adverse health effects occur.
In addition to ambient air pollution, indoor smoke is also a serious health risk for some 3 billion people who cook and heat their homes with coal and biomass fuels.
The harmful effects related to short-term respiratory exposure to atmospheric particulate matter include:                lung inflammatory reactions,        respiratory symptoms,        adverse effects on the cardiovascular system,        an increase in medication usage,        an increase in hospital admissions, and        an increase in mortality.        
However, when one looks at the harmful effects from long-term exposure, a far bleaker picture is seen. These effects include:                an increase in lower respiratory symptoms,        a reduction in lung function in children,        an increase in chronic obstructive pulmonary disease,        a reduction in lung function in adults, and        a reduction in life expectancy, owing mainly to cardiopulmonary mortality and probably to lung cancer.        
There is a great need for effective and practical microfiltration of inhaled air in order to reduce inhaled quantities of fine and ultra-fine pollutants and particulate matter such as smoke and dust. Current methods of addressing this widespread problem include face masks which usually cover the nose and mouth, physical nose filters that go outside the nose, or intrusive nose filters that are inserted into the nasal passageway. In general, these methods are inferior to the Present Invention as they are awkward, uncomfortable, cumbersome, and not effective in filtering ultra-fine particulate matter from inhaled air.